Progress bar for closing studies

[cosfor1]

It could be very helpful to show a thin progress bar on the bottom of a study, which will show the progress of the saving action called when a user clicks "Save and close" while switching to the dashboard.

[elisabettai]

This also would help with frustration that might build up when closing large studies and have to wait a long time, as discussed with @newton1985 during user testing before release